Carrier 50NQ Installation, Start-Up And Service Instructions Manual page 12

Table 5—Minimum Airflow for Safe
Electric Heater Operation
SIZE
018
024 030
036 042 048 060
AIRFLOW
(CFM)
600 800 1000 1200 ; 1400 1600 2000
Table 6—Wet Coil Pressure Drop
Unit Size Wet Coil P.D. (In. wc.)
018, 024
0.54
030
.060
036 .070
042
.075
048 .086
060
.100
UNIT TOP REMOVAL
A CAUTION
Condenser fan and motor are fastened to the unit top.
When removing the top, use extreme care not to puli
the fan motor leads loose.
NOTE:
When performing maintenance or service proce¬
dures that require removal of the unit top, be sure to per¬
form
all
of the routine maintenance procedures that require
top removal, including: coil inspection and cleaning, and
condensate drain pan inspection and cleaning.
Only qualified service personnel should perform mainte¬
nance and service procedures that require unit top removal.
Refer to the following top removal procedures:
1. Remove all screws that secure unit top, including
screws around four sides and those on top that screw
into internal divider panels. Save all screws.
2. Tape all side panels at each seam near unit top. Use
tape strips that are at least 5 ins. long to prevent sides
from falling when top is removed.
3. Lift top from unit carefully. Set top on edge and ensure
that top is supported by unit side that is opposite duct
(or plenum) side.Use
extreme care to prevent damage to
the fan blades, motor, and insulation.
4. Carefully replace and secure unit top to unit, using
screws removed in step 1, when maintenance and/or
service procedures are concluded. (Be sure to use origi¬
nal screws that have rubber washers to seal out water
when securing top to internal divider panels.)
INDOOR BLOWER AND MOTOR
For longer life, operating economy, and continuing effi¬
ciency; clean accumulated dirt and grease from the blower
wheel and motor annually.
A WARNING
Disconnect and tag electrical power to the unit before
cleaning the blower assembly. Failure to adhere to this
warning could cause personal injury or death.
Clean the blower assembly as follows:
1. Remove and disassemble blower assembly as follows:
a. Remove blower access door.
b. Disconnect blower motor leads from their termina¬
tion points at motor. Disconnect yellow lead from
control box at capacitor.
c. Remove blower assembly from unit. Be careful not
to tear insulation in blower compartment.
d. Ensure proper reassembly by marking blower wheel
and motor in relation to blower housing before
disassembly.
e. Loosen setscrew(s) that secures wheel to motor
shaft, remove screws that secure motor mount
brackets to housing, and slide motor and motor
mount out of housing.
2. Remove and clean blower wheel as follows:
a. Ensure proper reassembly by marking wheel orien¬
tation and cutoff plate location.
b. Remove screws holding cutoff plate, and remove
plate from housing.
c. Lift wheel from housing. When handling and/or
cleaning blower wheel, be sure not to disturb bal¬
ance weights (clips) on blower wheel vanes.
d. Remove caked-on dirt from wheel and housing with
a brush. Remove lint and/or dirt accumulations
from wheel and housing with vacuum cleaner, using
soft brush attachment. Remove grease and oil with
mild solvent.
e. Reassemble wheel and cutoff plate into housing.
f. Reassemble motor into housing. Be sure setscrews
are tightened on motor shaft flats and not on round
part of shaft.
OUTDOOR COIL, INDOOR COIL, AND CONDENSATE
DRAIN PAN
Inspect the coils and condensate drain pan at least once
each year. Proper inspection and cleaning requires the
removal of the unit top. See "Unit Top Removal" section.
The coils are easily cleaned when dry; therefore, inspect and
clean the coils either before or after each cooling season.
Remove all obstructions, including weeds and shrubs that
interfere with the airflow through the outdoor coil.
Straighten bent fins with a fin comb. If coated with dirt or
lint, clean the coils with a vacuum cleaner using the soft
brush attachment. Be careful not to bend the fins. If coated
with oil or grease, clean the coils with a mild detergent-and-
water solution. Rinse coils with clear water using a garden
hose. Be careful not to splash water on motors, insulation,
wiring, or air filter(s). For best results, spray outdoor coil
£ns from inside to outside the unit. On units with an outer
and inner outdoor coil, be sure to clean between the coils. Be
sure to flush all dirt and debris from the unit base.
Inspect the drain pan and condensate drain line when
inspecting the coils. Clean the drain pan and condensate
drain by removing all foreign matter from the pan. Flush
the pan and drain tube with clear water. Do not splash
water on the insulation, motor, wiring, or air filter(s). If the
drain tube is restricted, clear it with a "plumbers snake" or
similar probe device.
OUTDOOR FAN
A CAUTION
Keep the outdoor fan free from all obstructions to
ensure proper operation. Never place articles on top of
the unit.
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